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- Evaluation of antimicrobial susceptibility among Campylobacter jejuniPublication . Camilo, Rute; Mena, Cristina; Silva, Joana; Teixeira, Paula
- Characterisation of alheiras, traditional sausages produced in the North of Portugal, with respect to their microbiological safetyPublication . Ferreira, Vânia; Barbosa, Joana; Silva, Joana; Felício, Maria Teresa; Mena, Cristina; Hogg, Tim; Gibbs, Paul; Teixeira, PaulaThe objective of this study was the characterisation of alheiras, traditional Portuguese sausages, with respect to their microbiological safety. Thirty-eight lots from 17 producers were analysed. The microbiological status of the analysed product can be considered of concern in terms of food safety. Although Campylobacter spp. and Escherichia coli O157 were not detected in any sample,and Clostridium perfringens when present was not at levels of concern with reference to public health, Salmonella spp. were detected in 2 lots of industrially produced alheiras, and more than 60% of the lots analysed were contaminated with Listeria monocytogenes in concentrations higher than 100 cfu/g.
- Pesquisa de Listeria monocytogenes em produtos cárneos fumados e de salsichariaPublication . Vaz-Velho, Manuela; Almeida, Gonçalo; Mena, Cristina; Carneiro, Luisa; Freitas, António
- Pesquisa de Listeria monocytogenes em produtos cárneos fumados e de salsichariaPublication . Almeida, Gonçalo; Mena, Cristina; Carneiro, Luisa
- Study of Biological Hazards Present on the Surfaces of Selected Fruits and VegetablesPublication . Noronha, Lúcia; Castro, Ana; Ferreira, Vânia; Magalhães, Rui; Almeida, Gonçalo; Mena, Cristina; Silva, Joana; Teixeira, PaulaThis study evaluated the microbial load on the surface of fruits with rough and very pronounced textured peels, namely pineapples and melons (cantaloupe), and investigated the presence of foodborne pathogens in these products since they are usually eaten raw. Similarly, lettuce is one of the most common salad vegetables consumed raw in Portugal, it therefore being important to study the microbial status of lettuce leaves. Enumerations of aerobic mesophilic counts, Enterobacteriaceae, Escherichia coli and coagulase-positive staphylococci, as well as detection of Listeria monocytogenes and Salmonella spp., were performed for all samples. Only in melon samples were E. coli and coagulase-positive staphylococci not detected. Contamination with L. monocytogenes varied from 2.5% and 15% in pineapple/melon and lettuce samples, respectively. Salmonella spp. were not detected. All coagulase-positive staphylococci had similar characteristics and none exhibited multidrug resistance. L. monocytogenes isolates belonged to serogroups II (1/2c or 3c), or to serogroup IV (4b, 4d and 4e). None were found to be resistant to antibiotics commonly used in therapy of listeriosis.
- Food Safety in the domestic environment: incidence of Listeria monocytogenes in domestic refrigeratorsPublication . Marujo, Daniela; Pereira, Isabel; Mena, Cristina; Carneiro, Luísa; Almeida, Gonçalo; Teixeira, Paula; Gibbs, Paul
- Incidence of Listeria spp. in domestic refrigerators in PortugalPublication . Azevedo, Inês; Regalo, Mafalda; Mena, Cristina; Almeida, Gonçalo; Carneiro, Luísa; Teixeira, Paula; Hogg, Tim; Gibbs, Paul A.The main objectives of this study were to determine the incidence of Listeria spp. in Portuguese domestic refrigerators and to evaluate some of the hygienic practices in the domestic environment that might contribute to the persistence of the organisms. It was found that L. monocytogenes was present in 3 domestic refrigerators of the 86 investigated. L. grayi and L. innocua were also isolated from 4 and 1 refrigerators, respectively. Overall, the information obtained from our survey demonstrates the need for consumer education in Portugal regarding safe food handling practices. For the refrigerators investigated, ≈71% were operating at a temperature higher than 6.1ºC, 87% were cleaned only monthly or less frequently, and only 8% were cleaned with appropriate proprietary cleaning products available in supermarkets.
- Comparison of Oxford Agar, PALCAM and Listeria monocytogenes Blood Agar for the recovery of L. monocytogenes from foods and environmental samplesPublication . Pinto, Marlene; Burria, Solange; Mena, Cristina; Almeida, Gonçalo; Carneiro, Luísa; Teixeira, Paula; Gibbs, Paul A.This work had as the main objective a comparison between Listeria monocytogenes Blood Agar (LMBA) and the conventional selective agar media, Oxford and PALCAM, relative to its efficacy in the detection of L. monocytogenes in naturally contaminated food and environmental samples. 173 environmental samples and 272 samples of foods were analysed. A higher sensitivity for detection of L. monocytogenes was verified for LMBA than for PALCAM and Oxford. In LMBA L. monocytogenes could be distinguished from other Listeria spp. by detection of hemolysis. In Oxford and PALCAM this distinction was not possible. The higher growth rate of L. innocua cf. L. monocytogenes in selective liquid media could result in a high number of false negatives (non-detection of the target organism on plates, although its presence was observed by other tests, eg. mini-VIDAS LMO). The need for specific media for the detection of L. monocytogenes in food was confirmed. LMBA could be an alternative medium to use together with PALCAM or Oxford.
- Use of predictive modelling software in the evaluation of corrective actions, HACCP plans, within artesanal dairy productsPublication . Campelos, I.; Mena, C.; Gibbs, P.; Hogg, T.; Teixeira, P.
- Evaluation of the hippurate test as a method for the differentiation between Campylobacter jejuni and Campylobacter coliPublication . Mena, C.; Leite, D.; Silva, J.; Gibbs, P.; Teixeira, P.